I am using
You can not use
scrollToItemAtIndexPath:atScrollPosition:animated for this.
Hopefully, they will add a new method like
scrollToSupplementaryElementOfKind:atIndexPath: in the future, but for now, the only way is to manipulate the contentOffset directly.
The code below shows how to scroll header to be on top vertically with FlowLayout. You can do the same for horizontal scrolling, or use this idea for other layout types.
NSIndexPath *indexPath = ... // indexPath of your header, item must be 0 CGFloat offsetY = [collectionView layoutAttributesForSupplementaryElementOfKind:UICollectionElementKindSectionHeader atIndexPath:indexPath].frame.origin.y; CGFloat contentInsetY = self.contentInset.top; CGFloat sectionInsetY = ((UICollectionViewFlowLayout *)collectionView.collectionViewLayout).sectionInset.top; [collectionView setContentOffset:CGPointMake(collectionView.contentOffset.x, offsetY - contentInsetY - sectionInsetY) animated:YES];
Note that if you have non-zero
contentInset (as in iOS 7, when scroll views expand below bars) you need to subtract it from the
offsetY, as shown. Same for
The code assumes that the layout is in prepared, "valid" state because it uses it to calculate the offset. The layout is prepared when the collection view presents its content.
The call to
[_collectionView.collectionViewLayout prepareLayout] before the code above may help when you need to scroll the collection view which is not yet presented (from
viewDidLoad say). The call to
layoutIfNeeded (as @Vrasidas suggested in comments) should work too because it also prepares the layout.